In construction, determining the slope of a surface is an important skill in ensuring that the apparatus, item or structure being built is meeting proper specifications. For example, builders and carpenters often have to determine the slopes of surfaces for constructing houses, installing flooring, or the like. If a surface that is supposed to be sloped does not meet the specification set forth, then the structure may not meet proper codes and can lead to faulty construction. For example, determining the pitch of a roof is crucial in determining the shape and size of the roof as well as the amount of material to be used. On the other hand, other surfaces must be horizontally or vertically level.
Spirit levels have been developed to meet some or all of the above-identified needs. For instance, a spirit level can include one or more sealed tubes partially filled with fluid so as to define a bubble in the tube. The position of the bubble in the tube can be used to determine whether the surface is level. If one or more appropriately-configured arced tubes are used, the position of the bubble in the tube can be used to determine the slope or pitch of the surface.
Currently, commercially available levels use petroleum products such as alcohol or kerosene as the fluid in the tubes of the spirit levels. These fluids resist freezing yet have significant environmental and commercial drawbacks when the fluid is released from the tubes. These drawbacks include problems such as staining the areas where they are released, toxicity and creating potential fire hazards. Further, when a level is damaged or disposed of, it is sent to a landfill or other waste disposal area where the level is eventually broken and the fluid released into the environment.
Petroleum based fluids also have use limitations when temperatures vary at worksites due to expansion and contraction of the petroleum based fluids. At 37.78° C. for instance, the bubble in a petroleum fluid filled level is very small due to expansion of the fluid. This makes determining the slope measurement difficult as well as places additional stress on the seams and/or seals of the tube due to the expansion of the petroleum fluid. Additionally, lower temperatures, such as −7.0° C., result in petroleum based fluids contracting and creating a large bubble that is far to large to provide accurate slope measurements. Moreover, finding substitute fluids requires walking a fine line between introducing fluids that are too viscous, which results in the bubble moving slowly or not at all, or fluids that are not viscous enough which cause the bubble to “splinter” into smaller bubbles when the level is jarred thereby hampering the users ability to obtain reliable measurements.
Further, with the fluctuating price of petroleum products, using these as fluids in spirit levels can dramatically increase production costs in addition to the aforementioned drawbacks.
Accordingly, the need exists for an environmentally friendly yet renewable fluid that overcomes the drawbacks associated with using petroleum fluids in spirit levels.